Chemical apparatus and process disinfecting – deodorizing – preser – Control element responsive to a sensed operating condition
Patent
1984-02-02
1985-11-19
Lacey, David L.
Chemical apparatus and process disinfecting, deodorizing, preser
Control element responsive to a sensed operating condition
7386418, 222309, G01N 114
Patent
active
045541345
DESCRIPTION:
BRIEF SUMMARY
The present invention is concerned with a pipette with adjustable volume, which pipette comprises a frame portion shaped as a handle, a cylinder being formed inside the said frame portion, as well as a piston fitted into the cylinder by means of a seal ring, a piston rod connected to the piston, as well as a press knob with shaft, fitted at the upper end of the frame portion, and that, by turning the said press knob, a sleeve, which determines the upper position of the piston and which is non-rotable in relation to the frame portion of the pipette, can be displaced, by means of a threaded joint, upwards or downwards relative the shaft of the knob so as to adjust the volume of the pipette, and that the pipettable volume can be read numerically through an opening or window in the pipette frame by means of a series of rings consisting of numbered discshaped rings.
In prior art, several pipettes of the type concerned are known, but their construction is complicated or therein it is difficult to lock the volume at a desired value.
The pipette in accordance with the present invention is mainly characterized in that, above the uppermost ring in the series of rings, a ring-shaped spring is fitted non-rotably in relation to the frame portion of the pipette, the bottom face of the said ring-shaped spring being provided with globular projections designed to be jointly operative with notches provided in the end face of the ring, so as to lock the ring gently in the desired volume positions.
The invention comes out in more detail from the following description and from the attached drawing, wherein
FIG. 1 is a sectional side view of a pipette in accordance with the invention,
FIG. 2 shows a section along line A--A in FIG. 1,
FIG. 3 shows a section along line B--B in FIG. 1, and
FIG. 4 shows a section along line C--C in FIG. 3.
The frame portion 1 of the pipette, shaped as a handle, contains a cylinder 2, into which a piston 3 has been fitted by means of a seal ring 7. The seal ring 7 is kept in position in its groove by a ring flange 15 fitted above the ring, which ring flange is pressed downwards by a spiral spring 16 fitted around the piston rod 4 between the ring flange 15 and a flange portion 17 at the upper end of the piston rod 4. A disposable tip vessel 19 is attached to the lower end of the tip tube 18 connected to the lower part of the cylinder 2 in the frame part 1 of the pipette. The upper end of the piston rod 4 is pressed against the lower end of the shaft 6 of the press knob 5. A sleeve 20 is fitted by means of a threaded joint 21 around the shaft 6 of the press knob. Inside the frame portion 1 of the pipette, there is an annular limiter flange 22, against whose lower face the sleeve 20 rests by means of its upper face. In this way, the sleeve 20 together with the annular flange 22 determines the upper position of the piston 3. The inside of the frame portion 1 of the pipette is provided with longitudinal guides 23, and the sleeve 20 is provided with notches corresponding to the said guides 23, whereby the guides 23 and the notches prevent rotation of the sleeve 20 in relation to the frame portion 1 of the pipette, but permit axial gliding of the sleeve 20 inside the frame portion 1 of the pipette.
Above the adjustment thread 21 of the press knob shaft 6, on the press knob shaft 6 there is the calibration thread 8. The diameter and the pitch of the calibration thread 8 may be either the same as, or different from, those of the adjustment thread 21. By means of the calibration thread, a calibration sleeve 9 is fitted around the shaft 6 of the press knob 5, by means of which sleeve 9 the lower limit of the movement of the piston 3 during pipetting can be determined. As surrounded by the mantle 10 of the hollow press knob 5 and by the upper portion of the pipette frame 1, the calibration sleeve 9 is placed at a distance both from the mantle 10 of the press knob 5 and from the inside face of the cover of the upper part of the pipette frame 1. For the secondary movement of the pipette, an annular flange 11 is
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Fagerstedt Mikael
Kaski Erkki
Kukka Aarre
Tervamaki Jukka
Gzybowski Michael S.
Labsystems Oy
Lacey David L.
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